Mercedes says it would welcome Audi to formula one.
As Red Bull desperately seeks an alternative after splitting with Renault, rumours suggest the Volkswagen Group is now eyeing a project for its Audi brand.
The sting in those rumours has been blunted by the international VW diesel emissions scandal, but Mercedes - having ruled out working with Red Bull - says Audi would be good for F1.
"Another great manufacturer, and one of such high quality, is definitely in our interest," Mercedes’ F1 chief Toto Wolff told Germany’s Sport Bild.
"It would strengthen formula one as a platform," he insisted.
Mercedes team chairman and F1 legend Niki Lauda agrees: "Each new opponent is good for the sport."
It is suggested that one reason for Mercedes and Ferrari’s reluctance to supply Red Bull next year is nervousness that Audi will come in for 2018, benefitting from knowledge of the earlier engine collaboration.